1. Field of the Disclosure
This disclosure generally relates to a switching device and, more particularly, to a capacitive switch employing a reference circuit to improve the detection accuracy.
2. Description of the Related Art
Conventionally, the switch device uses a mechanical switch to detect the pressing of a user or the on/off status. However, the conventional mechanical switch may appear slow reaction due to poor electrical contact or failure due to the fatigue of elastic element after frequent operation.
Therefore, the industry proposed the capacitive switch that can detect the capacitance variation caused by a touch, e.g. detecting a change of oscillation frequency or charging duration, to accordingly identify whether a touch event occurs or not. However, the electrical offset may be generated in the conventional capacitive detection circuit due to the variation of the manufacturing process, operating voltage and temperature such that misidentification may occur during operation thereby decreasing the operation accuracy.
Accordingly, the present disclosure further provides a capacitive switch whose detection results are compared with the output of a reference circuit so as to eliminate the electrical offset caused by factors of the manufacturing process and operating environment thereby achieving higher detection accuracy.